The risk of needlestick injury and the expense associated with accessory cannulae, whether blunt or sharp, are well known. Conventional intravenous tubing systems utilize tapering luer male cannula connectors, often within an associated surrounding threadable member defining a luer-lock connector commonly used for achieving tight, sustained connections. A bare luer taper cannula without the associated threadable member is commonly called a luer slip connector and is widely utilized for brief prn injections. Both of these luer systems are in wide use throughout conventional hospital systems and it would be preferable to develop a connecting valve system which receives and is activated by conventional luer slip tapers or luer lock tapers so that incorporation into existing hospital systems is rapid and associated with minimal cost. It would be advantageous for such systems to avoid deadspace so that the surface could be easily wiped with antiseptic to avoid the need for capping after each use. Furthermore, the elimination of deadspace allows for the aspiration of blood through such systems without the collection of blood within the deadspace. Another important feature of such systems is the minimization of "kickback"--that is, it is important that the luer slip tip or luer lock systems, when not tightly locked, do not kickback out of the valve, thereby producing the potential for a spurt of blood or fluid into the environment and potential contamination of the operator.
The prior art includes several luer-receiving valves which do not have substantial deadspace. U.S. Pat. No. 5,201,725 shows a valve which utilizes an elastomeric member which opens by force induced by a threadable member over the elastomeric septum piston. Such a system will not work with a conventional luer lock system since the role taper extends centrally adjacent the luer lock threading member and therefore, it would not be possible to compress the septum piston within the luer-lock threads in such a system without inserting the male member itself into the septran piston. The background discussed in the aforementioned patent provides additional background for the present invention.
A device, designated the CLAVE.TM., for an injection port marketed by McGaw, is included in the Prior Art. This device utilizes a cannula surrounded by a septum piston. The septum piston is compressed by the luer taper, thereby allowing the needle and its associated bore to enter the bore of the luer taper, thereby opening fluid communication. However, such systems would be expected to be associated with substantial kickback when used with a luer slip system since the septum piston must be relatively resilient to prevent leakage associated with higher fluid pressures within the cannula. Further, tile requirement of a spike or cannula within the bore of the valve results in considerable increase in expense associated with complex insert molding of the device. It is, therefore, preferable to develop a more simplified valve system which can receive a luer taper cannula and which eliminates the need for complex insert molding to minimize the potential for kickback and the potential for trapped fluid or blood while still providing a deadspace-free surface which can be easily wiped with antiseptic. Such a device also will not receive a blunt cannulae and, therefore, may be difficult to implement with conventional drug delivery systems.
In general, the present invention comprises a housing including a main conduit having a main bore and further having a branch extending away from the main conduit and including a secondary bore extending through the branch in fluid communication with the main conduit. The secondary bore may be aligned directly with the main conduit or may branch from the main conduit. The main conduit may, for example, comprise a catheter or may be a primary intravenous tubing system or arterial line. The secondary bore defines a longitudinal axis. An elastomeric septum piston is disposed within the secondary bore and at least a portion of the elastomeric septum piston is moveable by either compression or by longitudinal advancement along the secondary bore toward the main bore. In one preferred embodiment, the septum piston is cylindrical and includes a centrally positional slit extending along the longitudinal axis of the cylindrical septum piston. The cylinder includes a proximal end and a distal end. The proximal end preferably extends to a position adjacent the proximal end of the secondary bore so that the surface of the proximal end of the septum piston is easily accessible adjacent the proximal end of the branch and therefore can be easily wiped with antiseptic. This is an important feature since it eliminates the need for capping after blood aspiration or drug injection. The bore of the secondary branch preferably includes two opposing projecting members along a distal portion of the bore which effectively narrow the diameter of the bore along at least a portion of one longitudinal axis. In the preferred embodiment, the central slit through the septum piston defines a longitudinal axis transverse to the longitudinal axis of the septum piston. With this embodiment, the longitudinal plane of the narrowed distal portion of the secondary bore is aligned with the longitudinal axis of the slit through the elastomeric septum piston. Furthermore, the elastomeric septum piston is sized to be transversely compressed by the projecting distal portions of the secondary bore. Since the slit is aligned with the projecting portions, transverse compression of the septum piston occurs along an axis which corresponds with the longitudinal axis of the slit so that when the elastomeric member is pushed from a proximal position into a distal position, the elastomeric member is transversely compressed by the projecting portions along the distal secondary bore, the compression causing the formerly tightly-closed slit to shorten and thereby open, allowing fluid to pass through a nascent flow channel formed by the shortened slit through the elastomeric septum piston. When the septum piston retracts away from the distal portion back into the proximal portion, the slit returns to its tightly closed position, thereby occluding further fluid communication through the septum piston.
In the preferred embodiment, the projecting portions progressively lengthen to define a progressively decreasing distance between the projecting members so that the projecting members are closer to one another adjacent the main bore than adjacent the proximal cylindrical portion of the secondary bore. This effectuates a progressive enlargement of the opening through slit of the elastomeric septum piston when the elastomeric septum piston is fully advanced into the proximal portion of the secondary bore. Furthermore, after removal of the luer, as the elastomeric septum piston retracts away from the distal compressing portion toward the proximal portion, the slit progressively closes from its proximal extent toward its distal extent, thereby expressing fluid toward the main bore rather than toward the proximal opening of the secondary bore. This reduces the chance of blood or fluid refluxing out of the septum piston into the environment or into the secondary bore when luer taper cannula is withdrawn from the secondary bore.
The septum piston can include a proximal extension which can be cylindrical and can be integral with the septum piston and can be formed of like elastomeric material such as silicone or latex rubber. The septum piston and the extension can be formed together as a single integral flexible conduit having an interior sterile enclosed flow path. In one embodiment, the proximal end of the conduit is closed to comprise the septum piston having a sealed perforation, as described above;the distal end of the conduit is opened and engages a seat which can provide a seal. The conduit therefore provides an enclosed flow path from the luer tip through the conduit when the closed end of the conduit is distorted such that the perforation is open. The distal open end of the conduit can be intussuscepted over a tube which can be rigid so as to provide a fixed sealed seat. Alternatively, the seat can be provided by a slot formed within an outer housing. An advantage of the tubular seat is that it provides easy mounting of the tubular flexible conduit during manufacture and further can provide an effective seal against contamination of the interior flow path within the flexible conduit during operation. It is considered potentially advantageous to provide an enclosed sterile central flow path which does not contact the housing to thereby minimize the potential for contact contamination of the flow path.
It can be seen that the flexible conduit in conjunction with the seat can provide both a sealed interior flow path and can further provide an additional elastic spring force when mounted with the rigid seat such that longitudinal force applied by insertion of the luer to the closed end of the conduit results in either longitudinal compression or folding of the tubular conduit which will then rebound to its original position when the longitudinal force applied by the luer tip is removed. Since the flow path need not engage the housing, the housing can be provided as only an incomplete cylinder or can be provided as linear support struts, thereby increasing visibility of the flexible conduit and fluid path and allowing more open access to the tabular seat for more easy molding and mounting of the flexible tubular conduit with the seat during manufacture.
In one embodiment, the proximal face of the septum piston of the tubular conduit is soft such that the face will mold with the distal tip of the luer when the luer tip is advanced against the face, thereby providing enhanced sealing of the luer with the face. The face can also include a circumferential membranous apron extending lateral to the face and over the distal end of the housing of the branch. The apron can then be deflected inwardly by the housing as the septum piston is advanced, thereby providing an additional circumferential seal for the luer tip. The rigid tube can be provided as a wedge or tapered cone member to assist in distorting the septum piston perforation into the open position.
A flow deflector or ramp can be provided when the housing of the branch is mounted to a tubing system to form a secondary branch, as in a T or Y configuration. The flow deflector can ramp flow into deadspace within the flexible conduit or rigid tubular seat so as to minimize the trapping of air bubbles or blood within the seat or flexible conduit when the device is used in blood sampling configurations, such as with arterial lines.
The branch of the main conduit can be aligned directly with or perpendicular to the main conduit or can be at an oblique or acute angle with the main conduit. The main conduit is generally discussed below as integral with the valve, but the main conduit may be a separate piece and sold separately, and may be joined with the branch or the aligned secondary bore by a threadable member as, for example, joining a conventional heparin well or prn adapter to a catheter, stopcock, or IV tubing system.
The branch preferably includes at least one external thread or thread receiver for receiving an internal female threading member to allow a secure threaded connection with a conventional luer-lock type connector of the type commonly used with conventional syringes or intravenous tubing systems.
The use of this luer-activated valve in association with IV piggyback administration generally would require the recapping of the luer taper after use so that the luer taper remains sterile between IV piggyback mediation administrations. My U.S. Pat. No. 5,167,643 (the disclosure of which is hereby incorporated by reference as if completely disclosed herein) describes a Docking Station for receiving a blunt cannula such as a tapered luer end to maintain the sterility of the tapered end. The present invention includes the secondary tubing system having a docking station intended for use with a conventional luer taper cannula of the slip tip or luer lock type. This station utilizes a simple membranous cover since the primary function of the cover is to cover and seal the luer within the station, as discussed in the previous patent. The new protection station may include an annular shield for protecting the fingertips against inadvertent contact of the luer taper since the luer taper has been removed from fluid connection with the patient's blood vessel and, therefore, could be contaminated by potentially infectious material which, by even surface contamination of a nurses fingers, could subsequently enter a fissure in the fingers or otherwise be transferred to a mucous membrane where infection could ensue. The station preferably includes a connecting portion for connecting to a proximal portion of the intravenous piggyback system or supporting pole, as described in my aforementioned patent. The combination of a primary fluid system which incorporates a luer-activated valve and a secondary system which incorporates a luer cannula protection station which protects the tapered blunt cannula of the luer provides reliable intermittent connection to the patient with assurance that the luer taper remains sterile between use and eliminates the need for the utilization of multiple caps, thereby reducing overall cost.
It is the purpose of the present invention to provide an inexpensive medical valve which can be activated by a conventional luer taper cannula and thereby be widely implemented within existing hospital systems.
It is further the purpose of the invention to provide a valve with a central sealed flow path through a flexible conduit, thereby minimizing the potential for contamination of the flow path and allowing for insertion of conventional blunt cannulae.
It is further the purpose of this invention to provide a medical valve which can be easily wiped with antiseptic to eliminate the need for recapping after use. It is further the purpose of this invention to provide a medical valve having substantially no deadspace adjacent its proximal portion to eliminate the pooling of blood or liquid within the valve so that the valve may be repetitively used for the aspiration of blood and reinjection of liquids.
It is further the purpose of this invention to provide a luer-activated opening of a central fluid path which is automatically aligned with the bore of the luer and which will directly communicate with the bore of a luer taper cannula upon the transmission of longitudinal force of the luer taper cannula against the septum piston, thereby providing a mechanism for the opening of a centrally-positioned fluid path at the same time tight sealing occurs adjacent the distal end of the luer taper cannula against the septum piston. It is further the purpose of this invention to provide a valve which progressively closes from its proximal extent to its distal extent, thereby expressing residual fluid from the valve away from the environment. It is further the purpose of this invention to provide a two-piece valve which can be simply manufactured by the insertion of an elastomeric septum piston into a rigid tubular structure, thereby avoiding the need for expensive and complex insert molding.
These and other features will become evident from the summary and detailed description described below. Furthermore, these and other objects and advantages of the invention will be further set forth in the description which follows and, in pan, will be learned from the description or may be learned by practice of the invention. The objects and advantages of the invention may be realized by means of the instrumentalities and combinations particularly pointed out in the appended claims.